This invention relates to a supercharged two cycle V type engine and more particularly to an improved engine having this configuration and scavenging arrangement therefor.
The advantages of two cycle engines in connection with simplicity and high output per unit of displacement are well known. However, the porting of the engine, which contributes to its simplicity, and the two cycle operation also gives rise to certain problems in connection with good performance. It is important to insure that the burnt charge is exhausted from the chamber completely during each cycle of operation and usually the intake charge is utilized to assist in the exhaust scavenging. However, there is a problem of overlap and the intake charge passing out of the exhaust ports. Either the lack of scavenging or excess scavenging and the loss of intake charge can degrade the performance of the engine.
To assist in scavenging, it has been proposed to employ some form of induction system that will introduce the charge at a greater than atmospheric pressure. Supercharging and turbo charging are typical ways in which this was done. However, with boosted engines, there is an additional problem in insuring that the intake charge does not pass out of the exhaust ports.
Furthermore, when the engine is designed as a V type engine, the provision of a supercharger also can give rise to difficulties in engine size. In some engines, the supercharger is placed between the banks of the V type engine but this tends to add to the size of the engine in that the banks may be spread more widely than may otherwise be normally desirable. In addition, the use of a centrally positioned supercharger tends to compromise the induction system and the scavenging ports and their location giving rise to the aforenoted problems of loss of intake air charge.
It is, therefore, a further object of this invention to provide an improved scavenging system for a two cycle V type engine.
It is a further object of this invention to provide an improved V type engine and supercharger and scavenging arrangement therefor.